Process of and apparatus for the combustion of solid fuel



Sept. 13, 1932. H. B. CANNON PROCESS OF AND APPARATUS FOR THE COMBUSTION 0F SOLID FUEL Filed o ct. 24. 1929 s sheets-stie 2 Sept. 13, 1932. H. B. CANNON- PROCESS OF AND APPARATUS FOR THE COMBUSTION OF SOLID FUEL 5 Sheets-Sheet 5 Filed Oct. 24P 1929 f IDIIJ taken on the line 3-3 of Fig. 1; Fig.- 3a a Patented Sept. 13, 1932- PrrENr OFFICE HIRA'M.' B. CANNON, OF ERIE, PENNSYLVANIA PROCESS F APPARATUS FOR THE COMBUSTION 0F SOLID FUEL` l Application led. October 24, 1929. Serial No. 401,998. I

This invention relates to a process of and apparatus for the combustion of solid fuel,

v and more particularly to a process of and apparatus for the combustion of bituminous lump and granular coal, or combinations of both forms, such as occur in what is known to the trade as run-of-the-mine coal, although it is believed that the process and apparatus possess utility in connection with the handling and combusti-on of hard coal and coke.

In realizing the objects of my invention, I employ a Ydownwardly inclined retort and combustion chamber, of refractory material,

y preferably silicon carbide, a material which I have employed in the combustion chamber shown, for instance, in my Patent No. 1,371,- 7 7 4, issued Mar. 15, 1921 and in Patents Nos.. 1,701,834 and-1,701,838, issued February 12, 1929.

' This downwardly inclined retort and combustion chamber discharges the resultant ash and slag into a suitable receptacle, preferably a trough, kprovided with a screw conveyor by F which the refuse material may be delivered Vlfrom the furnace structure without admission of air thereto. The fuel is delivered to the combined retort and combusti-on chamber at such rate and its rate of movement through .the said reto-rt and combustion chamber is such that, by the time it reaches the lower end of the same, dissociation of the solid fuel will have been completed, or substantially completed, with the delivery of molten ash and slag` and clinkers from the bottom .of the chamber into the trough. v

In practicing my invention, I employ an apparatus of thecharacter shown in the drawf ings, wherein Fig. 1 'represents' a fore-andaft sectional view through a furnace equipped with my invention, the view corresponding to the line 1-1 of Fig. 2; Fig. 2 a fragmentary front elevation, partly in section, of a furnace equipped with my invention; Fig. 3 a cross sectional view of the combined retort and combustionechamber, thesame being detail showing a modification ofthe apparatus illustrated in the preceding views and which adapts the invention for heating by radiation and by sensible heat; Fig. 4 a side elevation of a modified form of the combustion chamber and retort; Fig. 5 a sectional view through the latter retort and chamber, correspondingto the line 5 5v of Fig. 4'; Fig.

6 a side elevation of 'a still further modiilca- 55 tion of the retort and combustionfchamber; and Fig. 7 a section through the last mentioned chamber and retort corresponding to the line A7-7 of Fig. 6; and Fig. 8 a detail in section taken on the line 8 8 of Fig. 6 and 60 looking in the direction of the arrows.

Describing the various parts by referencel characters, and first in connection with Figs.

1 to 3 inclusive, 1 denotes the front wall, 2 the bottom, 3 the top, 4 the rear wall, and 5 u the side walls of a furnace which may be used for any desired industrial purpose and the details of the structure of which may be varied according to such use. In the embodiment shown herein, the space 6 above the com- 7 bustion chamber- (tobe described hereinaf# ter) is adapted to receive yarticles adapted to be heated by radiation from such chamber, and the top wall 3 is provided with outlets 7.

The bottom 2 of the furnace is shown as of considerable thickness and the top of the same is inclined downwardly Yfrom the front to the rear, as shown at 8, providing hearths the lower ends of which terminate short of the rear wall 4, between which and the lower ends of the hearths the furnace bottom2 is provided with a transversely extending ash pit 9 receiving a metal trough 10 in which is mounted a screwconveyor 11, which may be oper ated by any source of power, one end of the trough communicating with a pit 12 into' which the slag, ash (and cinder are delivered by the conveyor. This pit and the trough are sealed against the entrance of air by a door 13 through which the refuse may be removed from time to time.

Supported on the hearths 8 are a plurality of inclined retorts and combustion chambers, indicated generally at A, which may 'be of the form shown in Figs. 1 and 3, the number of such 4 retorts and combustion chambers depending upon the length and capacity of the furnace and the purpose rfor which it is intended. The chambers are made of refractory material having high heat radiating i accomplished by radiation only, the top andqualities, such as A1203, fused MgO, and sili-y con carbide, the last mentioned material b eing preferable because of its exceedingly high heat-radiating qualities.

In the form of my invention shown in Figs. l to 3, where the heating is intended to be sides of the chamber A project beyond the bottom and into engagement with the rear furnace wall 4 and the said wall is provided with an opening 14 located opposite the end of each chamber and provided with a plug 15 of suitable refractory material. Thls arrangement provides means of access to the chamber A for cleaning as well as for repairs.

Below each chamber A, the rear furnace wall 4 is provided with outlet openings 16 for discharging the products of combustion from the ash pit into a flue 16a.

Extending through the front wall of the furnace are casings 17, preferably of metal, there being one such casing for each combined combustion chamber and retort, each such casing having its lower end fitted within the upper end of such chamber. Each casing is provided with a flange 18 which engages a plate 19 on the front wall of the furnace and which plate surrounds theopenrng 20 through which the casing projects. Each casing is also provided with an upwardly extending neck 21 which receivesfuell from a hopper 22. Mounted in each casing 1s a hollow feed worm 23 the upper end of which projects through-a gear box 24 at the 'top of the` casing and communicates with an a1r supply pipe 25 to which air is suppliedunder pressure by means of a blower 26.

Within each box 24, each hollow worm is provided with a worm gear 27 meshing w1th a worm 28 on a shaft 29, which shaft may be driven by an electric motor, indicated generally at 30.

With the parts constructed and arranged as described, -assuming that the fuel employedv is the ordinary run-of-the-mine bituminous fuel, the said fuel is delivered by the worms 23 into the upper ends of the chambers A, air being supplied for combustion through the pipe 25 and the hollow worms 23. The fuel may be ignited by means of a torch introduced into the upper end of each chamber A through a firing plug or door 31 in the air line and in register with the outer end of each hollow worm 23. The fuel, being ignited, will move by gravity and in a more or less plastic condition to the bottom of the chamber A, the rate of feed and the length of the chamber being so proportioned that, bythe time thefuel reaches the lower end of the chamber, the progressive dissociation of the mass will have been completed,` the bottom of the chamber being covered with the fuel mass throughout its length. This mass varies in its physical and chemical characteristics during its progress from the receiving end to ation being from the solid fuel, through the plastic decomposing fuel, to the final molten slag, ash and clinker, which are delivered into the transverse ash pit 10. The ash will be partly in a plastic condition and partly in a granular form. However, the fuel will be delivered to the combustion chamber and fed therethrough at a rate which will enable it, to be completely converted into the gaseous elements and to be consumed in the chamber A by the time the fuel shall have reached the bottom of its chamber A.

In operation, I have found that, with a hearth 8 inclined downwardly at an angle of about 15 and with a combined retort and chamber A made of silicon carbide and having a cross sectional area of about 6" by 6 and a length of approximately 9 feet, I am enabled to obtain complete dissociation of the fuel when using run-of-the-mine bituminous fuel fed at the rate of from 6 tov 15 pounds of such coal per cubic foot of combustion space per hour, this rate of feed giving a heat release at the rate of from 72,000 to 180,000B. t. u. per cubic foot of combustion space per hour.

In Fig. 31 there is showna modification of the invention illustrated.I in Figs. 1 to 3 inclusive, which modification is intended to adapt my invention for heating articles by sensible heat as well as by radiant heat. In.

this view, the top and sides of the chamber A terminate short of the rear wall 4 of the furnace,- the bottom wall of the chamber being cut away as before to enable the refuse to bepdeposited in the ash pit, and the cleanout j opening 14 and plug 15 are correspondingly positioned so as to register with thevpassage in rthe said chamber, and the ash pit will preferably be shallower. The trough and ash pit in this case will not be sealed from the furnace proper.

In Figs. 4 and A5, I have shown a form of combined retort and combustion chamber B,

wherein the fuel is fed along the bottom wall B in the same manner as is the case with the embodiment of my invention hereinbefore described in connection with Figs. 1 `to 3; but a partition B2 is interposed between the bottom wall and the top wall B3, extending from the front of the chamber toward but spaced from the rear thereof, whereby there are provided a lower pass B4 and an upper pass B5, the gases resulting from the dissociation of the solid fuel having their combustion completed in the upper pass and being discharged from an opening BG in the front of ered at a point 'other than-that at which the 'ash and other refuse are discharged5'it also gives a greater heat-radiating surface and a greater heat-release capacity for a given cross section and length of chamber.I In other words, f or an over-all length of combustion chamber which is equal to that of the chamber shown inFigs. 1-3', there will be double the length of combustion pass and double the length of radiating surface. Y v

The form of chamber C shown in Figs. 6, 7 and 8 differs from that shown in Figs. 4 and only in that the passes C and C2 are arranged side by side instead of vertically, with the partition C3 arranged vertically instead of horizontally. In other respects, the com-l bustion chamber is the same as that shown in Figs. 4 and 5, the gases of combustion being delivered through an opening C4 in the top of the-second pass C2 and at the front of the chamber. If desirable, the front end of the second pass in the forms of my invention shown in igs. 4, 5, 6, 7 and 8 may be extended through the front furnace wall and there may each be connected with a stack. This 'construction will be adopted where it is desirable that the heating be effected by radiation alone.

The air which is supplied by the blower 2,6 is under a pressure of a few ounces only, and this pressure may be reduced afterthe aplplaratus is in operation, due to the stack u P By virtue of my invention, it is possible to.

'use all grades of sold fuels, including the lowest and cheapest forms, and to produce an apparatus which can compete, from an elliciency standpoint, with apparatus employing gas, oil, or pulverized coal.V Furthermore, in the operation of my furnace, I am enabled to obtain smokeless, as well as complete, combustion of low-grade solid fuels.

Having thus described my invention, what I claim is:

1. The herein described process of burning solid lump and granular fuel which con-f sists in introducing such fuel'into one end of a retort and combustion ,chamber having one or more walls of high heat radiating material, supplying air to said combined retort and combustion chamber, igniting the fuel so introduced, and conveying the fuel mainly by gravity through the said chamben at a rate which will insure complete dissociation of the same by the time the fuel mass shall have progressed to the delivery end of the said chamber. p

2. The herein described process of burning solid lump and granular bituminous fuel which consists in delivering such fuel continuously into the upper end of a downwardly inclined retort and combustion chamber composed of refractory material having high heat radiating qualities, supplying air to said combined retort and combustion issuing therefrom. I 6. In an apparatus for the purpose dechamber, igniting the fuel so introduced into the said chamber, and feeding the fuel to said chamber and conveying ittherethrough mainly by gravity at a rate which will insure the complete dissociation of the fuel by the time the fuel mass shall have reached the upper end of a downwardly inclined retort and combustion chamber composed of refractory material having high heat-radiating qualities', supplying air under low pressure to the fuel-receiving end of said chamber, igniting the fuel so introduced into the said chamber, and feeding the fuel to said chamber and conveying it therethrough mainly by gravity at a rate which will insure the complete dissociation of the fuel by the time the fuel mass shall have reached the lower end of the said chamber. i

4. The process of burning lump and granular bituminous fuel-which consists in feeding such' fuel continuously into the upper end of a downwardly inclined retort and combustion chamber formed of refractory material having high heat radiating qualities, igniting the fuel so introduced into the said chamber, supplying air under low pressure to the said chamber, and establishing the rate of delivery of fuel to said chamber and its rate of advance through said chamber so that the dissociation of said fuel will be substantially completed by and at the time when the fuel massv shall have reached the lower end of said chamber.

5. The process of burning lump and granu- .lar bituminous fuel vwhich consists in feeding such fuel continuously into the upper. endof a downwardly inclined retort and combustion chamber formed of refractory material having' high heat-radiating qualities, igniting the fuel so introduced into the said chamber, supplyingair under low pressure to the tablishing the rate of delivery of fuel to said chamber and its rate of advance through said chamber so that the dissociation of sa1d fuel will be substantially completed at the time when the fuel mass shall have reached the lower end of said chamber, and removing the resultant refuse without admission of additional air to the said chamber and to the gases scribed, the combination, with a working chamber, of a plurality of combustion chambers of high heat-radiating material therein,

each combustion chamber being yinclined downwardly from the front of the working chamber toward 'the rear thereof, common fuel-receiving end of said chamber, and esmeans for feeding into the, upper end of each combustion chamber a combustible mixture of air with granular or lump solid fuel, each of the said combustion chambers being out gf communication with the working cham- 7. In an apparatus for the purpose described, the combination, with a working chamber, of a plurality of combustion chambers of high heat-radiating material therein, each combustion chamber being 'inclined downwardly from the front of the working chamber toward the rear thereof, Common means for feeding into the upper end of each l extending downwardly from the front of said working chamber, a casing extending through i the front wall of the said chamber and into and substantially closing the upper end of the combustion chamber, a hollow worm in said casing having its delivery end at the front or receiving end of the combustion chamber, means for supplying lump or granulated solid fuel to said casing and to the exterior of the worm therein, means for rotating said worm, and means for supplying air for the combustion of the fuel through said worm and into the upper end of the com- I l bustion chamber.

9. A furnace having front and back walls and a bottom wall having a hearth sloping downwardly from the front wall toward therear wall and provided at the bottom of such4 hearth with anash pit, a combustion chamber of refractory material having high heat radiating qualities mounted on the said hearth, a casing extending through the front wall of said furnace and arranged to deliver solid fuel into the upper end of said chamber, a hollow worm mounted in said casing, means for delivering solid fuel to said casing, and meansfor rotating said worm, thereby to feed the delivered fuel from the casing into the upper end of said chamber, and means for supplying air under light pressure through said worm to the upper end of the said chamber.

10. A furnace having front and rear walls and a bottom wall having a hearth sloping downwardly from the front wall toward the rear wall and provided at the bottom of such hearth with an ash pit, a combustion chamber of refractory material having high heat radiating qualities mounted on the said hearth, a casing extending through the front wall of said furnace and arranged to deliver solid fuel into the upper end of said chamber,

a hollow worm mounted in said casing, means for delivering solid fuel to said casing,and means for rotating said worm, thereby to feed *the delivered fuel from the'casing into the upper end of said chamber, means for supplying air under light pressure through said worm to the upper end of the said chamber, and means for removing from said ash pit the refuse supplied thereto from the said chamber without admission of air to the furnace.

11. A furnace having front and rear walls and a bottom wall having hearths inclined downwardly from the front thereof and an ash pit at the lower ends of such hearths, a combustion chamber resting on each such hearth and composed of refractory material having high heat-radiating qualities, casings extending through the front wall of the furnace and each having its inner or rear end arranged to deliver fuel into the upper end,

of one of such chambers, a hollow worm in each casing, a hopper arranged to deliver solid fuel into each casing, means for driving all of said worms in unison, thereby to deliver fuel into the upper ends of the chambers, means for supplying air under light pressure through the said worms and into the upper ends of said chambers, and means for removing refuse delivered to the ash pit from the said chambers without admission of air therethrough to the furnace.

12. .A furnace having front and rear walls and a bottom wall having a hearth sloping downwardly from the front wall toward the rear wall and provided at the bottom of such hearth with an ash pit, a Combustion chamber of refractory material having high heatradiating qualities mounted on the said hearth and having its top and side walls extending to the rear furnace wall and its bottom wall extended to the bottom of said hearth and the ash pit being sealed from the access of air therethrough to the interior of the furnace, a casing extending through the front wall of the said furnace and arranged to deliver solid fuel into the upper end of said chamber, a hollow worm mounted in said Casing, means for delivering solid fuel to said casing, means for rotating said worm, thereby to feed the fuel from the casing into the upper end of said chamber, and means for `supplying'air under light pressure through said worm to the upper end of said chamber. In testimony whereof, I hereunto affix my 

